The invention relates to the use of the skis on floats in the aircraft landing gear. Takeoff speeds of conventional floats typically associated with aircraft are encountered by drag of floats on water and by airborne drag.
A preliminary search in the United States Patent and Trademark Office included United States and foreign patents in Class 244, Aeronautics, Subclasses 100A. 101, 105, 106 and 108.
As a result of the search the following U.S. Patents were uncovered:
U.S. Pat. Nos. 1,285,230, 1,689,807, 1,698,808; PA1 U.S. Pat. Nos. 1,817,047, 1,963,630, 2,062,384; PA1 U.S. Pat. Nos. 2,064,674, 2,306,269, 2,340,080; PA1 U.S. Pat. Nos. 2,345,140, 2,345,143, 2,364,845; PA1 U.S. Pat. No. 2,375,973, 2,399,346, 2,444,264; PA1 U.S. Pat. Nos. 2,507,913, 2,991,745, 3,190,587; PA1 U.S. Pat. Nos. 3,599,903, 4,027,835.
A number of patents are directed to inflatable type floats. However, none of the prior art discloses the specfic elements of the present invention.
U.S. Pat. No. 1,285,230 describes a geometry for distribution of load, by mechanical means, over the float.
U.S. Pat. No. 1,689,807 relates to means of manual extension of a rigid ski below a float for landing on snow or ice. Current rigid aluminum aircraft floats have sufficient integrity to permit occasional snow and ice landings and take offs. The problem with rigid hull-like floats is that concentrated loads shear or loosen rivets which permit leakage on subsequent return to water operation.
U.S. Pat. No. 1,698,808 relates to a ski with a streamlining metal cap to improve airborne efficiency.
U.S. Pat. No. 1,817,047 uses a selective blast of compressed air to break surface tension just prior to lift off. This patent also identifies the possible use of engine exhaust gas.
U.S. Pat. No. 1,963,630 relates to a means of positioning the attitude of the aircraft with respect to landing gear and also contains retractable wheels and a shock absorbing mechanism between the airframe and the floats.
U.S. Pat. No. 2,062,384 uses compressed air or exhaust gas discharged parallel to the hull surface so as to break the relationship between hull and water.
U.S. Pat. No. 2,064,674 relates to a means of absorbing shock between float and airframe.
U.S. Pat. No. 2,306,269 uses a mechanical mechanism to collapse an elastomeric housing and also describes a collapsible and retractable wing tip float.
U.S. Pat. No. 2,340,080 describes a specific geometry of a rigid ski shape for aerodynamic characteristics.
U.S. Pat. No. 2,345,140 has a means of providing heated air to the atmosphere or the inlet of the engine supercharger.
U.S. Pat. No. 2,345,143 relates to a mechanical means of expanding or contracting a float to either provide additional floatation or better aerodynamic air flow.
U.S. Pat. No. 2,364,845 refers to a vertical lifting effect on the hull through a pneumatic effect. I do not see how this is possible without providing some confinement for the air. The typical vee shape of the hull would let air escape up the sides--as shown in FIG. 3. No mention is made of breaking surface tension.
A question exists as to how much of a pneumatic cushioning effect for absorbing shock would be achieved with the relatively small volume of air that would be discharged through the floats or hull. This patent further refutes the potential of boundry layer control by stating at page 2, lines 9-13 that as soon as the hull is clear of the water, the control valve is closed by the pilot.
U.S. Pat. No. 2,375,973 describes a triangular geometry of a truss inside a pneumatic float to function as a load carrying member.
U.S. Pat. No. 2,399,346 discloses a retractable top deck as part of a rigid hull along with a mechanical retraction method.
U.S. Pat. No. 2,444,264 describes the use of mechanically actuated doors folding a pneumatically deflated float to provide minimum frontal area.
U.S. Pat. No. 2,507,913 has a permanently inflated gas bag of polyolefin resin which functions as a resilient float which may be more resistant to damage in striking the water on landing than other floats.
U.S. Pat. No. 2,991,745 describes a water ski with a rigid slotted nose which may reduce spray formed during emergence.
U.S. Pat. No. 3,190,587 discloses an inflatable means to change the hull shape for maximum efficiency. The inflatable bag smooths lines of a hydrodynamic hull configuration to the smooth shape required for efficiency as an aerodynamic body.
U.S. Pat. No. 3,599,903 describes a float with a high length/beam ratio hull for minimum drag with minimal volume for floatation. The hull is nearly submerged at rest. Rapid lift from water is obtained by a supercavitating hydrofoil.
U.S. Pat. No. 4,027,835 describes the use of a combination rigid hydrofoil/wheel configuration in combination with a rigid demountable boat hull which functions as a displacement member to provide floatation.